For me, reviews of all types, but mostly backed-up by recommendations by friends (including a few I hold in high regards here) and dealers (remote) I trust. Unfortunately, I don’t have many good HIFI dealers in my area except a couple good used dealers), and the one dealer who does carry very good stuff is very high end (albeit I got my used Vandersteen Treo’s from him that he took on trade), thus, I have had to purchase many of my components without listening and comparing.
It’s worked out well thus far, but I do a lot of reading, talking, and investigation now days.